Measuring Apparatus

ABSTRACT

A height measuring apparatus comprising a main body portion adapted for placement upon an object to be measured, and a movable portion which is movable relative to the main body portion, wherein the movable portion comprises a laser source and a photo detector, the movable portion being movable so that a laser beam from the laser source can be directed to the ground when the main body is placed on the object to be measured.

FIELD OF THE INVENTION

The present invention relates to an apparatus for measuring the heightsof subjects, in particular where the apparatus is placed on top of thesubject to be measured.

BACKGROUND OF THE INVENTION

There exist many instances where there is a requirement to accuratelymeasure the height of an object or subject. For example, during medicalexaminations the height of a patient is often recorded. Similarly, theheight of a horse is an important metric for classification purposes.Height is also a critical parameter in the management of cattle, sinceit dictates the ‘Frame Score’, which is used to dictate breeding andnutrition programmes. Such measurements are usually taken usingmeasuring tapes or sticks. These are considered direct measurements. Ameasuring stick generally comprises an upright wooden ruler marked outin suitable units, and has horizontal sliding arm or ‘cross-bar’ that isarranged perpendicularly to the ruler. The subject to be measured isthen stood upright alongside the ruler and the horizontal arm is lowereduntil it contacts the point on the subject where the height measurementis to be taken from. With a human, this point would be the top of thehead; with a horse this would be at the withers; and with a cow at thetop of its hip bone. The corresponding reading on the ruler at thispoint provides the height measurement.

Measuring sticks as described above present a number of drawbacks.Firstly there is an inherent potential for error in the measurementmade. This is because the measurement is taken on the vertical ruler andnot at the horizontal point of contact with the subject. In other words,the point of measurement is displaced. Consequently, if the sliding armis not perfectly perpendicular to the ruler, this an error is introducedinto the measurement. Similarly, error may be introduced by poorcalibration or due to the judgement of the user. Furthermore, the use ofmeasuring sticks involves significant noise. In the case of animals,this can cause distress and unwanted movement, leading to flawedreadings. Still furthermore, measuring sticks are by their nature, largeand lack portability and so their practical use is often restricted to afixed location. When transported, the size and construction of measuringsticks makes then susceptible to damage, and wear which causes thecalibration of such devices to be eroded over time, leading to furtherinaccuracies. Tapes are also prey to mistakes, particularly when usedfor vertical measurement. This is mainly because they are not made ofrigid material and can bend. In addition, in order to record ameasurement, users have to look at both the point of contact formeasurement whilst ensuring the base of the tape remains on the floor.Combining these tasks introduces huge scope for human error.

Alternative means of height measurement, such as rangefinders, areknown. Rangefinders measure from a distance from the target subject andrequire that a line of sight to both the bottom and top of the object ispresent and that the elevation of the rangefinder is known.

By way of example, trees are commonly measured this way whereby a laserrangefinder is used to measure the straight line distances to the topand bottom of the tree and an inclinometer is used to measure the anglesto the top and bottom of the tree. The heights of the tree above andbelow the level of the rangefinder are calculated and added to give thetotal height. This method suffers a number of drawbacks. In particular,there are many sources of user error; the method is time consuming; andit requires the person conducting the measurement to be able to carryout trigonometric calculations. Furthermore, this method is unsuitablefor accurately measuring the height of modestly sized subjects at closerange, i.e. where space is limited. The accuracy of this method is alsosignificantly affected if the laser rangefinder changes elevationbetween the two measurement stages. It is also almost impossible for acasual user to perform this measurement without introducing a change inelevation of one or more centimetre. Similarly, range finders are notappropriate for a single person to measure an animal as they measurefrom a distance, i.e. the animal cannot be kept still.

It is therefore an object of the present invention to provide ameasuring device which mitigates the disadvantages of the prior art.

SUMMARY OF THE INVENTION

Accordingly, in one aspect of the present invention there is provided aheight measuring apparatus adapted for placement upon the object to bemeasured, the apparatus comprising a main body portion and a movableportion, wherein the movable portion is movable relative to the mainbody portion and comprises a laser source and a photo detector.

The present invention advantageously provides a height measuringapparatus in which a laser beam can be directed at the ground in anon-perpendicular angle when the main body portion of the measuringapparatus is placed on the object to be measured. In this way, the laserbeam can obtain a clear line of sight to the ground by avoiding the bodybeing measured.

Advantageously therefore, the apparatus provides a means of taking ameasurement of height directly from the object to be measured using asingle point of reference, the point of reference being the ground whichsupports the object being measured.

In embodiments, the laser source and photo detector are locatedproximate, and in precise alignment with, each other.

Optionally, the laser source is provided with a lens and focus adjuster.

Optionally, photo detector is provided with a focus adjuster.

Optionally, the laser source and photo detector provide a laserrangefinder.

Optionally, the laser source is a laser diode.

Optionally, the main body portion and/or the movable portion comprisesone or more of a circuit board, batteries, a screen and an on/off switchwhich activates the apparatus.

It will be appreciated that the circuit board, batteries, a screen andthe on/off switch can each be located within the main body portionand/or the movable portion where appropriate.

Optionally, the on/off switch is provided on the main body portion andcomprises a trigger mechanism. The trigger mechanism is depressed oractivated when the main body portion is placed on the object to bemeasured. In this way, the trigger provides a signal which readies theheight measuring apparatus for use.

Optionally, the trigger mechanism extends into a space defined by arecessed portion provided on the main body portion.

Optionally, the trigger mechanism comprises a capacitive touch switch.

Optionally, the main body portion and the movable portion are eachprovided with at least one accelerometer based inclinometer.

Preferably, the or each accelerometer is a tri-axial accelerometer.

Conveniently, the at least one tri-axial accelerometer associated withthe main body portion is adapted to measure the angular orientation ofsaid main body portion.

Conveniently, the at least one tri-axial accelerometer associated withthe movable portion is adapted to measure the angular orientation ofsaid movable portion.

In this way, the position of the laser and the photo detector withrespect to the main body portion can be accurately determined and thedata values relating to spatial location being usable by a processingmeans in an overall height calculation.

In particular, the vertical offset distance (“h”) between the origin ofthe laser beam and the point of contact between the main body portionand the object to measured, is established.

In addition, the provision of inclinometers in the main body portion andthe movable portion that are in communication with a processing meansenables the angle incidence of the laser beam with the ground to bedetermined.

Conveniently, it has been found that when the laser beam is incident atthe ground at a shallow angle, there is still sufficient beam reflectedback along the path of incident laser beam for detection by the photosensor. In this way a measurement of straight line beam distance L canbe made.

Optionally, the measurement of straight line beam distance L isdetermined using a measurement of the phase angle between the amplitudewaveform of the transmitted laser beam and that of the reflected beam.

Conveniently, the processing means which runs firmware programmed oradapted to convert the combination of laser path distance (measured bythe photo detector in conjunction with the laser source) and laser pathangle data determined by the tri-axial accelerometers, together withknown constant dimensions of the apparatus, to obtain an accuratemeasurement of the height of the object being measured.

Preferably, the processing means is a microprocessor.

In one embodiment, the main body and movable portions are eachconstructed from respective shell halves which define housings whichhouse the necessary hardware, circuitry, processing means and powersource for the measuring apparatus.

In one embodiment, the movable portion is slidably connected to the mainbody portion.

Optionally, at one end of the main body the respective shell halves areeach formed having an outwardly curved side that terminates in anupstanding side wall.

Conveniently, the sidewalls are of a height such that when the shellhalves are mated together, the terminal edges of the respective sidewalls are spaced apart so as to define an elongate slot.

Optionally, at one end of the movable portion each shell half isprovided a corresponding inwardly curved side that terminates in a sidewall having a projection extending outwardly therefrom.

Conveniently, the projection extending outwardly from the side wall ofeach shell half of the moveable portion defines a groove, each groovebeing adapted to receive a terminal edge of a side wall of the mainbody.

Advantageously, when the respective shell halves of the movable portionare mated together, the respective projections together define asubstantially T-shaped member which engages in use with the elongateslot defined by the respective shell halves of the main body portion.

In this way, when the shell halves of the main body portion are matedtogether to form the completed measuring apparatus assembly, the movableportion is engaged with and slidable relative to the main body portion.In this way, the laser can be oriented at a range of different anglesrelative the main body portion so that the laser beam can be directed atwhatever angle is necessary to avoid the body being measured and toobtain a clear line of sight to the ground.

Optionally, the movable portion can be maintained (i.e. held inposition) at a desired angle with respect to the main body portion.

The invention further provides a method of obtaining a measurement ofheight of an object, the method comprising:

-   -   placing a measuring apparatus upon the object to be measured;    -   manually adjusting a movable portion of the measuring apparatus        so that a laser source and photo detector on the movable portion        establish obtain a line of sight to the ground or other surface        upon which the object to be measured is standing or is        supported;    -   activating the apparatus to send a frequency modulated laser        beam from the laser source to the ground and automatically        calculating the laser path distance (L) to the ground;    -   automatically determining the angle of incidence of the laser        beam φ with the ground and calculating the laser path angle θ;    -   automatically determining the vertical offset height (h) between        the laser source and the point of contact of the main body        portion with the object to be measured; and    -   automatically calculating vertical height (H) of the object        being measured; wherein the calculation for vertical height is        performed by a processing means using the formula H=L sin(θ)−h.

Desirably, the step of manually adjusting the movable portion of themeasuring apparatus comprises slidably moving the movable portionrelative to the main body portion.

The method further includes one or more of: displaying the calculatedheight on a display provided on the measuring apparatus; recordingcalculated height measurements; communicating height measurements to aremote server or servers; associating height measurement data withidentifiers which relate to the object(s) being measured; adjusting thefocus of the laser beam.

The preceding discussion of the background to the invention is intendedonly to facilitate an understanding of the present invention. It shouldbe appreciated that the discussion is not an acknowledgement oradmission that any of the material referred to was part of the commongeneral knowledge as at the priority date of the application.

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of those words, for example“comprising” and “comprises”, mean “including but not limited to”, andare not intended to (and do not) exclude other components, integers orsteps.

Throughout the description and claims of this specification, thesingular encompasses the plural unless the context otherwise requires.In particular, where the indefinite article is used, the specificationis to be understood as contemplating plurality as well as singularity,unless the context requires otherwise.

It will be understood that the word ‘ground’ as used throughout theclaims and description should not be construed to mean the surface ofthe earth only, but rather describes any surface which supports theobject being measured.

Features, integers or characteristics, and compounds described inconjunction with a particular aspect, embodiment or example of theinvention are to be understood to be applicable to any other aspect,embodiment or example described herein unless incompatible therewith.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a and 1 b are schematic illustrations showing a height measuringapparatus in accordance with the present invention and shown in openedand closed positions;

FIG. 2 a is a detailed exploded schematic drawing of the exemplaryheight measuring apparatus of FIGS. 1 a and 1 b;

FIG. 2 b is a detailed exploded schematic drawing of an exemplary heightmeasuring apparatus; and

FIG. 3 is a schematic cross-sectional illustration showing the principleof operation of an the height measuring apparatus in accordance with thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 a, 1 b, 2 a and 2 b, there is shownembodiments of an exemplary measuring apparatus 1 in accordance with thepresent invention.

The measuring apparatus 1 provides a means to measure the height of anexemplary object 50 (FIG. 3) when placed on said object at a positionfrom where the height measurement is to be taken. The measuringapparatus 1 comprises a main body portion 12 and a movable portion 14,wherein the movable portion 14 is movable relative to the main bodyportion and comprises a laser source 141 and a photo detector 144. Thephoto detector 144 preferably is a photo diode.

Measuring apparatus 1 is a slim, portable hand held device that can bestowed in a small space, for example a pocket of a garment or bag.Optionally, the apparatus has a thickness of 10 mm or less.

As the size constraints imposed upon the measuring apparatus mean thatit will not always span across, or project laterally from the point ofcontact with an object to be measured to an extent that a notionalvertical (i.e. perpendicular) line of sight can be established with theground surface below. Similarly, with certain objects the point ofcontact from which the height is to be measured may be obscured by otherfeatures of that object such that a notional vertical (i.e.perpendicular) line of sight cannot be established with the groundsurface below. An example of such an exemplary subject 50 is shown inFIG. 3 where the body of the subject blocks a perpendicular view to theground below, thereby preventing a substantially vertically directedlaser beam from reaching the ground. However, with the presentinvention, it has been found that a derived measurement of verticalheight can be made using a laser beam 51 (FIG. 3) that is incident atthe ground at an angle that is substantially less than 90 degrees. Theshape of the exemplary subject 50 shown in FIG. 1 is generallyrepresentative of a horse or other animal.

With reference to FIGS. 2 a and 2 b, the main body 12 and movable 14portions are each constructed from respective shell halves which definehousings which house the necessary hardware, circuitry, processing meansand power source for measuring apparatus 1.

As shown in the embodiment of FIG. 2 a, the main body portion 12comprises a circuit board 122, batteries 123, a LCD screen 124 and anon/off switch 125 which activates the apparatus. The circuit board 122supports a processing means (not shown) which runs firmware programmedor adapted to convert the combination of laser path distance (measuredby the photo detector 144 in conjunction with the laser source 143 asdescribed below) and laser path angle data, together with known constantdimensions of the apparatus, to obtain an accurate measurement of theheight of the object being measured. Preferably, the processing means isa microprocessor. The height measurement is displayed on the LCD screen124 for immediate reading by a user.

It will be appreciated that the specific location of the respectivecircuitry, power supply and processing means is not limited to being inone or other of the main body 12 and movable portions 14. For example inthe arrangement shown in FIG. 2 b, the battery 123 and circuit board 122are shown located within the movable portion 14.

In the embodiment shown in FIGS. 1 a, 1 b and 2 a, the on/off switch 125is provided on the main body portion and comprises a trigger mechanism125 a. The trigger mechanism 125 a can be depressed or activated whenthe main body portion is placed on the object to be measured. In thisway, the trigger mechanism can provide a signal which readies the heightmeasuring apparatus for use. In FIG. 2 b a further transparent cover1240 is shown placed over screen 124.

As shown in FIGS. 1 a, 1 b and 2 a, the trigger mechanism 125 a may beprovided to extend into a space defined by a recessed portion 127provided on an edge 120 of the main body portion 12. Such a recess 127enables the measuring apparatus to engage positively with the withers ananimal, for example a horse.

In an alternative arrangement as shown in FIG. 2 b, the on/off switchcomprises a capacitive touch switch 125 b that is housed within the mainbody portion 12.

As shown by way of example in FIG. 2 b, the measuring apparatus furthercomprises a socket 128, such as a USB connector, to enable externalconnection of the apparatus for the purposes or powering, batteryrecharging, data transfer and the likes.

Referring to FIGS. 1 a, 1 b and 2 a, the movable portion comprises alaser source 141, such a laser diode, and a photo detector 144 (FIG. 2a, 2 b), the photo detector being located proximate to, and in precisealignment with, the laser source 141 and adapted to receive reflectedlaser light from said laser source. A lens 142 (FIG. 2) and focusadjuster 143 are also provided for control and adjustment of the beam oflaser light emitted from the laser source 141. A focus adjuster 145 isprovided in conjunction with the photo detector 144 in order to maximisethe amount of reflected laser light that can be captured. The laserdiode 141 and photo detector 144 together provide a laser range finder.In FIG. 2 b, the movable portion is shown having two laser diodes 141,each with associated lens 142 and focus adjuster 143. In this way, onelaser diode is a primary IR laser for the purposes of height measurementand which is invisible to the human eye, while the other laser diode isa visible laser to create a spot on the ground that is visible to theuser of the apparatus. It will be appreciated that while the two laserdiodes 141 of the arrangement in FIG. 2 b are shown having their ownrespective lens and focus adjusters, it is possible that the a commonlens may be shared. It will be appreciated that a single, visible, lasercan be employed therefore obviating the requirement for a separatesecondary laser diode to provide a visible spot.

In the embodiments as shown in FIGS. 1 a, 1 b, 2 a and 2 b and asdescribed below, the movable portion 14 is slidably connected to themain body portion 12.

With reference to FIGS. 2 a and 2 b, at one end of the main body portion12, the shell halves are each formed having an outwardly curved sidethat terminates in an upstanding side wall 121. The sidewalls are of aheight such that when the shell halves are mated together, the terminaledges of the respective side walls 121 are spaced apart so as to definean elongate slot (121 b, FIG. 1 b). At one end of the movable portion 14each shell half is provided a corresponding inwardly curved side thatterminates in a side wall having a projection 146 extending outwardlytherefrom, the projection defining a groove 147. Each groove 147 isadapted to receive a terminal edge of a side wall 121 of main body 14.When the respective shell halves of the movable portion 14 are matedtogether, the respective projections 146 together define a substantiallyT-shaped member which engages in use with the elongate slot 121 bdefined by the respective shell halves of the main body portion 12. Thuswhen the respective shell halves of the main body 12 and movable portion14 are mated together to form the completed measuring apparatus assembly(as shown in FIGS. 1 a, 1 b), the movable portion 14 is engaged with andis slidable relative to the main body portion 12. In this way theconnection of the movable portion to the main body portion is a slidinghinge. In this way, the laser 141 can be oriented at a range ofdifferent angles relative the main body portion 12 so that the laserbeam can be directed at whatever angle is necessary or appropriate toavoid the body being measured and to obtain a clear line of sight to theground. Conveniently, the geometry and/or dimensions of thesubstantially T-shaped member and the elongate slot 121 b are such thatthey mutually frictionally engage in use, such that the movable portion14 can dwell at any position to which it is moved with respect to themain body portion 12. Advantageously therefore, the movable portion 14can be maintained (i.e. held in position) at any desired angle withrespect to the longitudinal axis of the main body portion 12.

It will be appreciated that the movable portion 14 is movable relativeto the main body portion 12 such that the laser 141 and photo diode 144may be oriented an any angle between 0°-89° relative to the longitudinalaxis A-A (FIG. 1) of the measuring apparatus to provide a heightmeasurement. For example, in FIG. 1 the movable portion 14 issubstantially in alignment with the main body portion 12 (i.e. the hingeis at a “closed” or 0° position). In this orientation, whereby the 141and photo diode 144 are aligned substantially perpendicular to thelongitudinal axis A-A of the measuring apparatus, a height measurementcan be made by placing part or all of the movable portion 14 ofmeasuring apparatus outwardly over an edge of the object to be measured.

As shown in FIGS. 2 a and 2 b, a dust cover 129 is provided between themain body portion 12 and the movable portion 14.

It will be appreciated that the movable portion 14 may alternatively bearranged to be pivotally movable with respect to the main body portion12. For example, the movable portion 14 may be connected to the mainbody portion 12 by means of a hinge. Similarly, the movable portion maybe rotatable with respect to the main body portion 12.

Conveniently, a port 148 provided in movable portion 14 allows forelectrical connection of the powered components of said movable portion14 with the hardware, circuitry, processing means and power sourcehoused within the main body portion 12.

It has been found that even when the laser beam 51 is incident at theground surface which supports the object being measured a shallow anglethere is still sufficient beam reflected back along the path of incidentlaser beam for detection by the photo detector 144. Thus a measurementof straight line beam distance can be made (as indicated by distance “L”in FIG. 3).

The measurement of distance L is determined by modulating the laserlight is amplitude modulated with a high frequency wave (10-20 MHz) andthen comparing this modulating waveform with the corresponding waveformobtained from the reflected signal as detected by the photo detector 144adjacent to the source 141 of the laser beam. The beam reflected fromthe ground will manifest a phase delay compared with the modulatingsignal as a consequence of the time of flight incurred by the distancetraveled by the laser beam along the return journey from the laser beamsource to the ground and back. Accordingly, the phase angle or delaybetween the amplitude waveform of the transmitted beam 51 and that ofthe reflected beam is a direct function of the time of flight. Thusmeasurement of the phase angle indicates the time of flight. As thespeed of light is a constant, and as the time of flight is known fromthe phase angle, the length of the beam path, i.e. distance L, can becalculated. This phase delay is extracted using a conventionalheterodyne circuit within the measuring apparatus whereby the highfrequency signals are mixed with a common local oscillator signal toobtain two resulting signals that have much lower frequency but the samephase angle as the original pair of signals (modulating and reflected).At this lower frequency this phase angle is determined by a simplemicroprocessor timer circuit incorporated within the measuring apparatusand/or in communication with the processing means.

In normal circumstances, the fraction of laser light that is reflectedback along the beam path (51, FIG. 3) is so small it would ordinarily bediscarded as worthless and is therefore ignored. However, with thepresent invention it has been found that the loss in reflected laserlight is tolerable such that an accurate distance measurement can bemade using the apparatus of the present invention.

Main body portion 12 and the movable portion 14 are each provided with atri-axial accelerometer 130. The tri-axial accelerometer associated withthe main body portion 12 is adapted to measure the angular orientationof said main body portion 12. The tri-axial accelerometer associatedwith the movable portion 14 is adapted to measure the angularorientation of said movable portion. The respective tri-axialaccelerometers 130 are in communication with the processing means. Thus,the position of the laser 141 and the photo detector 144 with respect tothe main body portion 12 can be accurately determined and the datavalues relating to spatial location being usable by the processing meansin an overall height calculation. In particular, the distance “h” (seeFIG. 3), which is the vertical offset distance between the origin of thelaser beam and the point of contact between the main body portion 12 andthe object to measured, is established. In addition, the provision oftri-axial inclinometers in the main body portion 12 and the movableportion 14 which are in communication with a processing means enablesthe angle of incidence φ of the laser to the ground to be measured andthe laser path angle θ (theta) to be determined.

The use of tri-axial accelerometer in both the main body portion 12 andthe movable portion 14 means that a user is not required to bemeticulous in placing the measuring apparatus 1 in a horizontalorientation on the object to be measured. This is because the tri-axialaccelerometers and associated processing means can automaticallycompensate for apparatus orientation in use and relative hinge angle inorder to correctly determine the true angle of the laser beam. Inaddition, they can also determine and make correction for any minorvertical offset of the source 141 of the laser beam 51 arising frominclination of the measuring apparatus from an optimum horizontalorientation.

As described above, the processing means, optionally a microprocessor,runs firmware programmed or adapted to convert the combination of laserpath distance L, offset height h and laser path angle data θ, togetherwith known constant dimensions of the apparatus to obtain an accuratemeasurement of the vertical height H of the object being measured. Thecalculation for vertical height is performed by the processing meansusing the formula

H=L sin(θ)−h

The resultant height measurement is displayed on the LCD screen 124 forimmediate reading by a user. Conveniently, the calculated verticalheight can be displayed in appropriate units selected by the user andchosen from a menu stored on the processing means.

With reference to FIG. 2 b, an example of a mode of use of the apparatuscomprises the following steps:

a) holding the apparatus by gripping the main body portion 12;b) tapping and holding the area on the main body portion 12 which isproximate the capacitive touch switch 125 b to activate the apparatus;c) after a delay of approximately two seconds the display 124 activatesand pressure on the capacitive touch switch 125 b can be released;d) placing an edge 120 of the main body portion 120 of the apparatusonto an upper surface of the object to be measured, the apparatus beingheld in an approximately level orientation;e) tapping the main body portion 12 proximate the capacitive touchswitch 125 b to activate measurement mode;f) adjusting the movable portion 14 so that the laser establishes a lineof sight to the ground;g) tapping the main body portion 12 proximate the capacitive touchswitch 125 b in order to freeze the displayed height measurement;h) if necessary, tapping main body portion 12 proximate the capacitivetouch switch 125 b again to reactivate measurement mode;i) tapping and holding the main body portion 12 proximate the capacitivetouch switch 125 b to turn off the apparatus; or alternativelyk) leaving the apparatus for approximately 30 seconds for automaticswitch off.

As the operation of the measuring apparatus is instantaneous and silent,it is particularly suited for use in the measurement of horses. This isbecause horses generally do not stand still for sufficiently longperiods to make accurate measurements using traditional techniques andbecause they are easily unsettled by unfamiliar noises in closeproximity. It will be appreciated however the a height measuringapparatus in accordance with the present invention is not limited to usewith animals, but rather is suitable for use with anything which theapparatus can be placed in contact.

Conveniently, the measuring apparatus optionally includes the followingbeneficial features:

-   -   Date and time stamping of measurements made    -   Photo, video and/or audio recording means    -   Scanning and reading RFID or other chip-based technologies    -   Wireless communication with remote server    -   Interfacing with “smart” devices and applications (“apps”)        running on said devices    -   Means to sense vital signs and/or take appropriate biometric        measurements    -   Ability to receive or upload pre-prepared data sets (e.g. lists        of people, patients, animals etc.)    -   The ability to measure other physical dimensions and parameters        of physical space.

While the embodiments of the invention have been described as being slimand pocket-sized, it would be understood that the size of the measuringapparatus is not limited. For example, where heights to be measured aresubstantially greater than that of a human or animal, more powerfullaser diodes, photo detectors and batteries etc. may be required and sothe apparatus may require accordingly increased dimensions. In otherwords, it will be appreciated that height measuring apparatuses inaccordance with the present invention may be particularly optimized formeasurement of specific height ranges that are appropriate to particulargroups of subjects that are most commonly measured by specific usergroups.

It will be understood from the foregoing description that the apparatusin accordance with the invention provides a number of distinctadvantages, which include the ability to use a laser beam that can beinclined at an angle from the horizontal and shone at the ground with noaiming mechanism and no requirement to aim at any particular referencepoint or target on the ground. In this way the need for accurate aimingmechanisms, eye pieces, tripods and specific specialised training etc.is obviated. Furthermore, through the provision of a movable portion,the angle of the laser beam can be configured at an optimum angle tosuit a shoulder of an object being measured. Still furthermore, the useof a plurality of tri-axial accelerometers provides automaticcompensation for any angle of apparatus orientation in use and therebyobviates any requirement for a user to be exact in how the apparatus isplaced on the object being measured. Thus minimum user skill isrequired.

1. A height measuring apparatus comprising a main body portion adaptedfor placement upon an object to be measured, and a movable portion whichis movable relative to the main body portion, wherein the movableportion comprises a laser source and a photo detector, the movableportion being movable so that a laser beam from the laser source can bedirected to the ground when the main body is placed on the object to bemeasured.
 2. A height measuring apparatus as claimed in claim 1, whereinthe main body portion and the movable portion are each provided with atri-axial accelerometer, the tri-axial accelerometers being configuredto measure the angular orientation of the respective main body andmovable portions.
 3. A height measuring apparatus as claimed in claim 2,wherein the laser source, the photo detector and the tri-axialaccelerometers are in communication with a processor, the processorbeing configured to determine the angle incidence of the laser beam tothe ground, and to determine the vertical offset distance between the ofthe laser source and the point of contact of the main body portion withthe object being measured.
 4. A height measuring apparatus as claimed inclaim 3, wherein the laser beam is frequency modulated, and wherein theapparatus is configured to measure the phase angle or phase delaybetween the amplitude waveform of laser beam transmitted from the lasersource and that of the reflected beam from the ground to the photodetector.
 5. A height measuring apparatus as claimed in claim 4, whereinthe movable portion is connected by a hinge to the main body portion. 6.A height measuring apparatus as claimed in claim 5, wherein the movableportion and the main body portion are each constructed formed fromrespective shell halves, which define housings that house the lasersource, the photo detector, the tri-axial accelerometers, the processor,a battery power source, a display and an on/off switch of the heightmeasuring apparatus.
 7. A height measuring apparatus as claimed in claim6, wherein the shell halves of the main body portion are each formedhaving an outwardly curved side that terminates in an upstanding sidewall, wherein the sidewalls are of a height such that when the main bodyportion shell halves are mated together, the terminal edges of therespective side walls are spaced apart so as to define an elongate slot,and wherein the shell halves of the movable portion are each formedhaving a inwardly curved side that terminates in a side wall having aprojection extending outwardly therefrom, whereby the respectiveprojections define a T-shaped member when the movable portion shellhalves are mated together, and wherein the T-shaped member of themovable portion is adapted to slidably engage with the correspondingelongate slot of the main body portion.
 8. A height measuring apparatusas claimed in claim 7, wherein the slidable engagement of the T-shapedmember of the movable portion and the elongate slot of the main bodyportion is a frictional sliding engagement so that the laser source andthe photo detector on the movable portion can be oriented and maintainedat an angle between 0°-89° relative to a longitudinal axis of the mainbody portion.
 9. A height measuring apparatus as claimed in claim 8,wherein the laser source is a laser diode and the photo detector is aphoto diode, and wherein the each of the laser diode and photo diode areprovided with a focus adjuster.
 10. A method of obtaining a measurementof height of an object, the method comprising: placing a measuringapparatus upon the object to be measured; manually adjusting a movableportion of the measuring apparatus so that a laser source and photodetector on the movable portion establish obtain a line of sight to theground or other surface upon which the object to be measured is standingor is supported; activating the apparatus to send a frequency modulatedlaser beam from the laser source to the ground and automaticallycalculating the laser path distance (L) to the ground; automaticallydetermining the angle of incidence of the laser beam φ with the groundand calculating the laser path angle θ; automatically determining thevertical offset height (h) between the laser source and the point ofcontact of the main body portion with the object to be measured; andautomatically calculating vertical height (H) of the object beingmeasured.
 11. The method of claim 10, wherein the calculation forvertical height is performed by a processing means using the formula H=Lsin(θ)−h
 12. The method according to claim 11, including displaying thecalculated height on a display provided on the measuring apparatus. 13.The method according to claim 11, including recording calculated heightmeasurements.
 14. The method according to claim 13, includingcommunicating height measurements to a remote server or servers.
 15. Themethod according to claim 14, including associating height measurementdata with identifiers which relate to the object(s) being measured. 16.The method according to claim 10, including adjusting the focus of thelaser beam.
 17. The method according to claim 10, wherein the step ofmanually adjusting the movable portion of the measuring apparatuscomprises slidably moving the movable portion relative to the main bodyportion.